Muffler



June 29, 1965 P. F. JETTINGHOFF MUFFLER Filed May 27, 1963 INVENTOR Ew/217277171; 20%

United States Patent 3,191,715 MUFFLER Paul F. Jettinghofi, Jackson,Mich, assignor to Walker Manufacturing Company, a corporation ofDelaware Filed May 27, 1963, Ser. No. 233,265 Claims. (Cl. 181-47) Thisinvention relates to mufilers for automotive exhaust systems.

It is an object of the invention to provide a tri-flow gas path in anextremely small size muffler.

It is another object of the invention to provide a rnufiier foreffectively silencing the intermediate frequency range of exhaust gasnoises which is especially adapted for use in the newly developedtailpipe silencing exhaust system of the present assignee wherein amultiplicity of small diameter (about 4 inches maximum) silencingcomponents are distributed throughout the entire length of an exhaustsystem.

The invention comprises a three-part rnufiier in which a pair ofoverlapped tubes inside a shell provide a tri-flow path for gas flowingthrough the mufiier.

The invention is illustrated in the accompanying drawings in which:

FIGURE 1 is a longitudinal cross section through a mufiier embodying theinvention; and

FIG. 2 is a cross section along the line 22 of FIG. 1.

The mufiler 1 has a shell 3, an inlet tube 5, and an outlet tube 7. Thetubes 5 and 7 are inclined to the axis of the shell but substantiallyparallel to each other. They overlap and are spotwelded together asindicated by the x.

The shell 3 is originally an open ended cylinder having the largediameter shown in the drawings. The overlapped tubes are inserted insuch cylinder and then the ends thereof are reducedin a suitable manner,preferably by a swaging (axial compression) operation so that the endsof the shell are formed into end walls 9 and 11 and inlet and outletbushings 13 and 15. In this process the outer ends of tubes 5 and 7 arealigned with and brought into a tight press fit with the insides ofbushings 13 and 15, as seen at 17 and 19. They are then spotwelded tothe bushings as seen by the Xs. The bushings 13 and 15 may extend beyondthe ends of the tubes 5 and 7, as shown, to provide a means forconnection to other components in an exhaust gas system.

The walls of tubes 5 and 7 are louvered, as seen at 21 and 23,preferably over the full length thereof that is inside of the gas flowchamber 25 formed by shell 3. The bulk of the gas entering the inletbushing 13 will flow out of the outlet end 27 of tube 5 and then mustreverse its' direction of flow and flow back through'chamber 25 and thenreverse again to enter the inlet end 29 of the tube 7 to flow out of themuffler through bushing 15. High pressure pulses of gas can expand outthrough the louvers in each tube to be silenced in chamber 25. Somecross bleeding or flow through the louvers 21 and 23 can take place toprovide for minimum back pressure.

Patented June 29, 1965 ice In a commercial embodiment for certain 1963US. automotive exhaust systems, the tube 5 is of 2 inches OD. and thetube 7 is 1% inches OD. The bushings 13 and 15 are 2 inches I.D., theend 19 of tube 7 being expanded during the swage down of the outletbushing 15 by use of a suitable expansion mandrel. The louvers are .060inch round type. Tube 5 is 7 /4 inches long and tube 7 is 6 inches long.The length of chamber 25 is about 11 /2 inches. The outer diameter ofshell 3 is about 4 inches and the inner wall thereof contacts the edgesof the tubes 5 and 7 at the overlap to provide lateral support againstrattling.

It will be seen that despite the small size of the muffler 1 substantialbreak-up of slugs of gas occurs and effective silencing of intermediatefrequencies can occur with a minimum back pressure. The louversthemselves will also act to silence some of the high frequency noise inthe gas.

While the inlet and outlet bushings 13 and 15 are shown in axialalignment, it is possible that in some applications it may be desirableto ofiset their respective axes.

I claim: 7

1. A small size tri-flow muffler consisting of only three parts, saidthree parts being an inlet tube and an outlet tube partially overlappingthe inlet tube so that gas flowing from one to the other must reverseits direction of flow twice, the third of said three parts being anouter shell of no more than about 4 inches outer diameter providing achamber surrounding said inlet and outlet tube, said shell havingreduced diameter end portions forming an inlet bushing and an outletbushing, said bushings being in tight engagement respectively with endsof the inlet and outlet tubes, the inner diameter of the shell beingsubstantially the same as the maximum width of said two tubes at theoverlapped portion whereby said tubes contact said shell and said shellfurnishes lateral support for the overlapped ends of said tubes.

2. The invention set forth in claim 1 wherein the wall of said inlettube inside said shell is louvered.

3. The invention set forth in claim 1 wherein the wall of said outlettube inside said shell is louvered.

4. The invention set forth in claim 1 wherein the walls of said inletand outlet tubes inside said shell are louvered.

5. The invention set forth in claim 1 wherein the overlapped portion ofsaid inlet and outlet tubes are spotwelded together and said tubes arespotwelded to said bushings.

References Cited by the Examiner UNITED STATES PATENTS 1,991,748 2/35Johnson.

2,138,477 11/38 LudloW 18l-54 2,357,791 9/44 Powers 18l54 2,548,965 4/51Gaugler 181-36.2 2,583,366 1/52 Engels.

LEO SMILOW, Primary Examiner.

1. A SMALL SIZE TRI-FLOW MUFFLER CONSISTING OF ONLY THREE PARTS, SAIDTHREE PARTS BEING AN INLET TUBE AND AN OUTLET TUBE PARTIALLY OVERLAPPINGTHE INLET TUBE SO THAT GAS FLOWING FROM ONE TO THE OTHER MUST REVERSEITS DIRECTION OF FLOW TWICE, THE THIRD OF SAID THREE PARTS BEING ANOUTER SHELL OF NO MORE THAN 4 INCHES OUTER DIAMETER PROVIDING A CHAMBERSURROUNDING SAID INLET AND OUTLET TUBE, SAID SHELL HAVING REDUCEDDIAMETER END PORTIONS FORMING AN INLET BUSHING AND AN OUTLET BUSHING,SAID BUSHINGS BEING IN TIGHT ENGAGEMENT RESPECTIVELY WITH ENDS OF THEINLET AND OUTLET TUBES, THE INNER DIAMETER OF THE SHELL BEINGSUBSTANTIALLY THE SAME AS THE MAXIMUM WIDTH OF SAID TWO TUBES AT THEOVERLAPPED PORTION WHEREBY SAID TUBES CONTACT SAID SHELL AND SAID SHELLFURNISHES LATERAL SUPPORT FOR THE OVERLAPPED ENDS OF SAID TUBES.